The VARL Gene Family and the Evolutionary Origins of the Master Cell-Type Regulatory Gene, regA, in Volvox carteri

2007 ◽  
Vol 65 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Leonard Duncan ◽  
Ichiro Nishii ◽  
Alexandra Harryman ◽  
Stephanie Buckley ◽  
Alicia Howard ◽  
...  
Keyword(s):  
Gene Family ◽  
Regulatory Gene ◽  
Cell Type ◽  
Volvox Carteri ◽  
Evolutionary Origins

scholarly journals The genetic basis for the evolution of soma: mechanistic evidence for the co-option of a stress-induced gene into a developmental master regulator

2020 ◽  
Vol 287 (1940) ◽  
pp. 20201414
Author(s):  
Stephan G. König ◽  
Aurora M. Nedelcu
Keyword(s):  
Cell Fate ◽  
Stress Responses ◽  
Regulatory Gene ◽  
Somatic Cells ◽  
Cell Types ◽  
Volvox Carteri ◽  
Developmentally Regulated ◽  
Evolutionary Origins ◽  
Increased Sensitivity ◽  
Multicellular Organisms

In multicellular organisms with specialized cells, the most significant distinction among cell types is between reproductive (germ) cells and non-reproductive/somatic cells (soma). Although soma contributed to the marked increase in complexity of many multicellular lineages, little is known about its evolutionary origins. We have previously suggested that the evolution of genes responsible for the differentiation of somatic cells involved the co-option of life history trade-off genes that in unicellular organisms enhanced survival at a cost to immediate reproduction. In the multicellular green alga, Volvox carteri , cell fate is established early in development by the differential expression of a master regulatory gene known as regA . A closely related RegA -Like Sequence ( RLS1 ) is present in its single-celled relative, Chlamydomonas reinhardtii . RLS1 is expressed in response to stress, and we proposed that an environmentally induced RLS1 -like gene was co-opted into a developmental pathway in the lineage leading to V. carteri . However, the exact evolutionary scenario responsible for the postulated co-option event remains to be determined. Here, we show that in addition to being developmentally regulated, regA can also be induced by environmental cues, indicating that regA has maintained its ancestral regulation. We also found that the absence of a functional RegA protein confers increased sensitivity to stress, consistent with RegA having a direct or indirect role in stress responses. Overall, this study (i) provides mechanistic evidence for the co-option of an environmentally induced gene into a major developmental regulator, (ii) supports the view that major morphological innovations can evolve via regulatory changes and (iii) argues for the role of stress in the evolution of multicellular complexity.

Orthologs and paralogs of regA, a master cell-type regulatory gene in Volvox carteri

2006 ◽  
Vol 50 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Leonard Duncan ◽  
Ichiro Nishii ◽  
Alicia Howard ◽  
David Kirk ◽  
Stephen M. Miller
Keyword(s):  
Regulatory Gene ◽  
Cell Type ◽  
Volvox Carteri

scholarly journals Molecular evolution of the plant R regulatory gene family.

Genetics ◽  
1994 ◽  
Vol 138 (3) ◽  
pp. 849-854
Author(s):  
M D Purugganan ◽  
S R Wessler
Keyword(s):  
Molecular Evolution ◽  
Gene Family ◽  
Plant Species ◽  
Regulatory Gene ◽  
Nonsynonymous Substitution ◽  
R Genes ◽  
Nucleotide Substitutions ◽  
Variable Regions ◽  
Helix Loop Helix ◽  
Regulatory Loci

Abstract Anthocyanin pigmentation patterns in different plant species are controlled in part by members of the myc-like R regulatory gene family. We have examined the molecular evolution of this gene family in seven plant species. Three regions of the R protein show sequence conservation between monocot and dicot R genes. These regions encode the basic helix-loop-helix domain, as well as conserved N-terminal and C-terminal domains; mean replacement rates for these conserved regions are 1.02 x 10(-9) nonsynonymous nucleotide substitutions per site per year. More than one-half of the protein, however, is diverging rapidly, with nonsynonymous substitution rates of 4.08 x 10(-9) substitutions per site per year. Detailed analysis of R homologs within the grasses (Poaceae) confirm that these variable regions are indeed evolving faster than the flanking conserved domains. Both nucleotide substitutions and small insertion/deletions contribute to the diversification of the variable regions within these regulatory genes. These results demonstrate that large tracts of sequence in these regulatory loci are evolving at a fairly rapid rate.

Evolution of a regulatory gene family: HOM/HOX genes

1993 ◽  
Vol 3 (6) ◽  
pp. 931-938 ◽  
Author(s):  
Claudia Kappen ◽  
Frank H. Ruddle
Keyword(s):  
Gene Family ◽  
Hox Genes ◽  
Regulatory Gene

scholarly journals Differential repair of DNA damage in the human metallothionein gene family.

1988 ◽  
Vol 8 (12) ◽  
pp. 5331-5338 ◽  
Author(s):  
S A Leadon ◽  
M M Snowden
Keyword(s):  
Dna Damage ◽  
Gene Family ◽  
Transcriptional Activity ◽  
Initial Rate ◽  
Uv Damage ◽  
Cell Type ◽  
Specific Expression ◽  
Cell Type Specific Expression ◽  
Processed Pseudogene ◽  
Cell Type Specific

We studied the repair of UV- and aflatoxin B1 (AFB1)-induced damage in the human metallothionein (hMT) gene family. After exposure to either UV or AFB1, DNA damage was initially repaired faster in the DNA fragments containing the transcribed hMT-IA, hMT-IE, and hMT-IIA genes than in the genome overall. By 6 h posttreatment, there was at least twice as much repair in these genes as in the rest of the genome. Repair of UV damage in the hMT-IB gene, which shows cell-type specific expression, and in the hMT-IIB gene, which is a nontranscribed processed pseudogene, was about the same as in the rest of the genome, whereas repair of AFB1-induced damage was deficient in these two genes. Inducing transcription of the three expressed hMT genes with CdCl2 or of only the hMT-IIA gene with dexamethasone increased the initial rate of repair in the induced genes another twofold over the rate observed when they were transcribed at a basal level. The rates of repair in the hMT-IB and hMT-IIB genes were not altered by these inducing treatments. Transcription of the hMT genes was transiently inhibited after UV irradiation. Inducing transcription of the genes did not shorten this UV-induced delay. Thus, the efficiency of repair of damage in a DNA sequence is dependent on the level of transcriptional activity associated with that sequence. However, an increased efficiency in repair of a gene itself is not necessarily coupled to recovery of its transcription after DNA damage.

Sign in / Sign up

Export Citation Format

Share Document